Discussion - Large Jib Window


Temporary #3 Large Jib Window

As you know, we had an experimental program (X-jib) to establish if larger windows could be used in jibs to improve safety without increasing cost or reducing sail life. The program was very successful but had to wait for adoption until we had an approved set of Rules in the new ISAF format. While we are not finally settled, the RYA and IAA Rules both have identical ‘closed’ rules regarding sails and we are hoping that we can get unanimous approval for headsail window rule revision for interim adoption, until the change can be approved by our AGMs. Basically, we think that this change should not be controversial and it can be passed in the way we have done for the past number of years. This will permit safer jibs with larger windows to be purchased almost immediately and used in next year’s Internationals.

After carefully reviewing the jibs specially prepared for the X-jib program we think that the window size can be essentially doubled from the maximum permitted at present and still maintain its normal sail life. The sail makers said that this would not affect the cost of the sail. One very large window would be a bad idea because it could not help but pass across a current seam line, so 2 windows would be definitely preferred. However, we think it best to specify maximum total window area and up to two windows without further restrictions. We also think that the stressed area between the tack and clew must be avoided and have specified the lowest part of the window cannot be closer than 150mm to the straight line between tack and clew, rather than the present limitation which is 150mm to the foot of the sail. A number of current sails have been checked and we believe that no old sails will be made illegal by this change.

The proposed changes have been unanimously approved by the IRC and are stated below with the current rule for comparison.

International Rules Committee, David S. Weaver, Chairman